Records from state investigators have revealed the first clue about what may have happened to thousands of dollars missing after a West German dog-buying trip taken for the Sheriff`s Office by Sgt. Thomas McGinn.

Florida Department of Law Enforcement investigators wrote in a report released last week that McGinn, after his April 1983 trip, made $6,000 in ``unexplained`` cash deposits into his private bank accounts.

That fact, FDLE agents wrote, formed part of what they believed could be a grand theft case against McGinn.

They cited other evidence too:

-- West German dog-seller Hugo Mahr told investigators McGinn paid substantially less for two dogs than the prices McGinn claimed in receipts he submitted to the Sheriff`s Office.

An FDLE report also noted that Doug Phipps, the Sheriff`s Office personnel director, told an investigator that McGinn had experienced serious financial difficulty and had defaulted on a $5,000 credit card debt.

That evidence, however, was not enough to convince a Palm Beach County grand jury last month that McGinn should be charged with grand theft, a felony punishable by up to five years in prison.

Instead, for submitting the receipts, the grand jury indicted McGinn on charges of filing four false official statements, each a second-degree misdemeanor punishable by up to 60 days in jail.

FDLE agents refused comment on the case, except to say they stand by their reports. Treasure Coast State Attorney Bruce Colton and Assistant State Attorney Ed Miller could not be reached, but in the past have refused comment about why specific charges were or were not filed.

McGinn`s attorney Barry Krischer could not be reached for comment, but has said his client plans to fight the charges.

McGinn has been suspended without pay, pending the outcome of his trial.

The FDLE and Colton`s office were assigned by Gov. Bob Graham on Dec. 14, 1984, to investigate McGinn and Sheriff Richard Wille.

That joint investigation began, at Wille`s request, after the News/Sun- Sentinel published on Dec. 9 and 10, 1984, results of its own investigation of McGinn and Wille.

Those articles revealed McGinn inflated purchase prices and submitted forged or untraceable receipts after three government-sponsored trips to West Germany on which he claimed to have spent $58,000 to buy 23 dogs.

The newspaper`s interviews with dog-sellers in West Germany showed that McGinn had inflated dog prices by $9,200, submitted to the Sheriff`s Office six phony receipts and another nine receipts for $19,998 that did not contain a complete signature or traceable address.

Wille benefited financially from the trips when he used McGinn to buy him at least five personal dogs but paid less in expenses than other buyers.

The grand jury on May 29 cleared Wille of any criminal or ethical wrongdoing and indicted McGinn for filing the four false receipts and lying on his Sheriff`s Office application.

The records released last week by prosecutor Ed Miller relate only to the part of McGinn`s first trip that is relevant to the indictment. Miller released the records as part of the procedural discovery process prior to McGinn`s trial.

In Deputy Zeichman`s sworn statement, he told investigators he thought he was filling out the receipts because McGinn was ``very poor at paperwork.`` He also said he did not understand why McGinn asked him to change his style of writing when he signed the receipts in another person`s name.

After the newspaper articles appeared, Zeichman said he talked to McGinn about the ``bad press,`` but not about the receipts.

Later, shortly before his interview with investigators, a worried Zeichman said a sheriff`s sergeant advised him that he had two options: ``You can either go (to the interview) and try to forget everything you ever knew, or else you can call (Personnel Director) Doug Phipps.``

In his statement, Phipps said Director of Administration Jerry Nolan had expressed suspicions that McGinn was inflating purchase prices.

Nolan, records show, denied any impropriety in the way expenses for personal dogs were allocated. Wille benefited coincidentally, he said.

He also said McGinn inappropriately used Sheriff`s Office money to buy personal dogs in West Germany for Wille and other individuals, but the Sheriff`s Office was reimbursed.

Although Phipps never got a dog bought in West Germany, he said he got a puppy that was ``the illicit prodigy of the liaison between (Sheriff Wille`s) dog and one of (McGinn`s) dogs.``